Therapeutic proteins, or 'biologics', represent a >$140 billion market that includes a variety of important drugs such as antibodies and hormones. The clinical efficacy of many biologics is determined by their sugar structures, or 'glycans'. Most biologics are manufactured in mammalian cells because they add human-type glycans, which are needed for the drug to function effectively. However, mammalian cells have some serious disadvantages. For example, it takes a long time to establish production cell lines, and mammalian cells can produce immunogenic glycans. The baculovirus / insect cell system (BICS) offers an attractive alternative system for biologics manufacturing, as it lacks these disadvantages. However, the BICS is currently limited by its inability to produce proteins with human-type glycans. GlycoBac has developed tools and methods to 'glycoengineer' insect cells, allowing them to add human-type glycans to recombinant proteins. In Phase I of this SBIR project, GlycoBac established the feasibility of producing several insect cell lines that can efficiently produce proteins with clinically relevant human-type glycan structures. Recently, it was discovered that GlycoBac's insect cells harbor a previously unknown virus. In Phase II, we will remove this adventitious agent using a proprietary method recently developed by GlycoBac. This will improve the biosafety profile of our glycoengineered cell lines and increase their value for biologics production. We will also produce two new cell lines that add two different kinds of 4-branched glycans to proteins. Such glycans are known to improve the efficacy for some vaccines and other biologics. Another Phase II Aim is to demonstrate the robustness and scalability of our new cell lines, as a key requirement for commercial use of the new cell lines will be demonstrated utility under production conditions. Finally, we will generate cell banks for two glycoengineered cell lines. These will be selected based on the performance of the cell lines combined with commercial prospects. In summary, our project is designed to develop glycoengineered BICS into a versatile platform with proven utility for the production of safe and efficacious biologics at production scales. The outcome of this Phase II SBIR project is expected to be a set of insect cell lines that can be used to produce a wide range of biologics with the specific human-type glycans that provide optimal efficacy for a particular application. The proposed products will have high potential impact as new tools for commercial protein manufacturing. GlycoBac also will make glycoengineered BICS available for academic and industrial, basic and applied research. Thus, the tools generated in this project will have a significant and broad impact on human medicine and diverse areas of basic biomedical research.